Clamping device for emery cloth and sandpaper



IT 4? J WW Sept, M, 195% H. J. HOBDAY 9 3 CLAMPING DEVICE FOR EMERY CLOTH AND SANDPAPER Filed Aug. 24, 1953 ATTX Patented Sept. 14, 1954 UNITED STATES PATENT OFFICE CLAMPING DEVICE FOR EMERY CLOTH AND SANDPAPER This invention relates generally to the class of tools and is directed particularly to abrading tools.

A principal object of the present invention is to provide a novel and improved tool or holder for abrasive sheets such as sandpaper, emery cloth or the like, wherein a means is provided for easily and quickly clamping the abrasive sheet in tightly drawn out condition across the face of a carrier block.

Another object of the invention is to provide an abrasive sheet holding device wherein a carrying block is provided at each of two opposite ends with a pivotally mounted frame carrying a spring pressed bar which is drawn around a curved end portion of the block when the frame is swung into holding or clamping position, whereby the bar draws the abrasive sheet tightly into place and also firmly clamps it.

Still another object of the invention is to provide an abrasive sheet holder or carrier of the above described character wherein the clamping or securing means by which the abrasive sheet is held in place on the block operates to effectively hold the sheet without the employment of screws, fasteners or other locking devices, the drawing of the sheet into tight condition and clamping it so, being effected entirely automatically with the swinging of the clamping bar carrying frame to locked or sheet holding position.

Other objects and advantages of the invention will become apparent as the description of the same proceeds and the invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming a part of the specification, with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

In the drawing:

Figure l is a view in plan of the underside of the abrasive sheet holding device of the present invention showing the clamping frames in sheet holding or looking position.

Figure 2 is a longitudinal section taken substantially on the line 2-2 of Figure 1.

Figure 3 is a view in transverse section taken substantially on the line 3-3 of Figure 1.

Figure 4 is a detail section taken substantially on the line 44 of Figure 1.

Referring now more praticularly to the drawing it will be seen that the main body of the abrasive sheet holding device comprises a solid block of material which is generally designated I0 and which may be made of wood, metal or any other suitable material.

The block body In is of elongate rectangular outline and at each end the bottom surface of the block is rounded to form the curved shoulder l2 and this curved shoulder merges with the reverse, curve or cove [4 which has its bottom slightly above the top face Illa of the block so that there is provided the narrow end wall It.

Each end of the block I0 is straddled by a clamping frame which is generally designed l8 and which is in the form of a Wide U. Each of these frames has the central bar portion 20 and the two right angularly extending end legs 22. These legs are in spaced parallel relation and are materially shorter than the width of the frame as shown but are spaced apart a sufficient distance to receive the width of the block Ill between them.

Each clamp frame has an end of the block [0 between the ends of the legs 22 thereof and each leg has extended therethrough a pivot screw 24 which is threadably engaged in the adjacent side of the block as indicated at 26. Thus each clamping frame I8 can be swung on an axis extending transversely of. the block and when the frame is swung to the hereinafter described abrasive sheet holding position, the cross bar 26 thereof will be positioned outwardly from the adjacent end of the block and in opposed parallel relation therewith as shown in Figures 2 and 4.

Positioned between the two legs 22 of each clamping frame [8 is a clamp bar 28 which is of a length substantially equal to the width of the block I0.

Adjacent to each end of the central part 20 of each clamping frame, such part 20 has formed therethrough a guide opening 30 in which is slidably positioned a guide pin 3| which has a head 3 l a which abuts the outer side of the clamping frame bar 20 while the inner end of the pin is secured as indicated at 32, in the adjacent end of the clamp bar 28.

Between the pair of guide pins 3| the bar portion 20 of each clamping frame has a number of recesses or sockets formed therein as indicated at 33 and the side of the clamping bar 28 facing these sockets is provided with a corresponding number of similar sockets 34.

Interposed between each clamping bar 28 and the middle or bar portion 20 of the adjacent frame is a number of short relatively strong springs 35, each of which has one end ina socket 33 and its other end in a socket 34 of thefadjacent clamping bar. These springs function to' force the clamping bar 28 inwardly toward the adjacent surface of the block It.

In securing a sheet of abrasive paper to the working face of the block l0, such piece of paper in the proper width, is placed lengthwise of the block upon the working or bottom face lllb and is provided with sufiicient length to extend beyond the ends of the block. In placing the paper in this position the clamping frames are swung to a position where the bars 28 will be opposed to the block face b and after placing the paper or abrasive sheet, which is here designated S, in'

the stated position, the clamping frames 88 are swung on their pivot pins 24 so as to place the frames IS in parallel planes and in the plane of the block 10. This action will cause the clamping bars 28 to slide around the rounded end shoulders I2 and come to rest in the coves l4 and this sliding action will draw the abrasive sheet tight against the face of the block and the pressure of the springs 35 will cause the bars 29 to tightly clamp the sheet in position.

As is clearly shown in Figure 2 the clamping frames 18 and the bars 28 are of a thickness of the block in so that when the clamping frames are in abrasive sheet holding position the clamping frames will not come into contact with the work when the working face of the abrasive sheet is placed thereon and the block moved over the surface to be smoothed.

From the foregoing description it will be seen that there is provided by the present invention a relatively simple device by means of which a sheet of abrasive material can be firmly clamped in place against the working face of the carrying block and such sheet will be held tightly in position while the block is being used. Thus the user of the device will have both hands free to hold the block or to use one hand for holding the block and the other hand for steady'ing the material and will not be concerned with holding the abrasive sheet and the block together while in use as would be the case if the customary practice were being followed of folding the abrasive sheet around a block and holding it in position with the same hand employed for sliding the block and abrasive sheet over the surface of the work.

I claim: I

1. An abrasive sheet holder comprising an elongate rectangular block body, said body having a recess formed across each end, a clamping frame straddling each end of the body, means pivotin each frame to the body to turn on an axis extending transversely of the body, said frames being adapted to be swung into a common plane in the plane of the block body and each frame having a straight center portion which is in spaced parallel relation with the adjacent end of the body when the frame is in said plane, and a spring pressed clamp bar carried by the frame in position to enter the adjacent end recess when the frame is swung into said plane.

2. An abrasive sheet holder as set forth in claim 1, wherein each of said frames is of wide U form in which the said center portion joins at each of its ends with a short leg, the block body being between said legs, and guide pins carried by said clamping bars and having sliding connection with the adjacent frame center portion.

References Cited in the file of this patent UNITED STATES PATENTS Number Name I Date 955,575 Bell Apr. 19, 1910 1,183,444 Fisk May 16, 1916 1,320,299 Wilson 'Oct. 28, 1919 2,429,550 Hein Oct. 21, 1947 2,446,625 Anderson Aug. 10., 1948 2,475,476 Champayne July 5, 1949 

